In January 2009, Marcello left the Chute Boxe Academy in Curitiba to go full on with his own martial arts academy, CM System, which opened its doors in March 2009. Despite leaving Chute Boxe, Marcello is still considered a BJJ coach, and continues to train Chute Boxe fighters out of his own gym.[4]

In February 2012, it was revealed that Marcello was selected to be a participant on The Ultimate Fighter: Live.[5] In the opening round, Marcello defeated Jared Carlsten by submission to qualify as one of the 16 fighters to live in the TUF house.[6]

Marcello was selected as Team Faber's second pick (fourth overall). In the second fight of the first round, Marcello was selected to fight Justin Lawrence, Team Cruz's first overall pick. He was knocked out by Lawrence at 3:15 of the second round.[7]

Cristiano made his return against Reza Madadi on October 13, 2012 at UFC 153.[9] He won the fight via a controversial split decision. The decision was controversial since most major MMA outlets scored the bout for Madadi. [10][11][12][13]

Marcello faced Joe Proctor on February 15, 2014 at UFC Fight Night 36.[15] He lost the fight via unanimous decision and announced his retirement 2 months later to focus more on his gym and coaching, Marcello also plans to compete in the ADCC for the first time in his grappling career.[16]